iwlwifi: protect use_ict with irq_lock

This variable was accessed without taking the lock.

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/drivers/net/wireless/iwlwifi/pcie/rx.c b/drivers/net/wireless/iwlwifi/pcie/rx.c
index d6860c0..be143eb 100644 (file)
--- a/drivers/net/wireless/iwlwifi/pcie/rx.c
+++ b/drivers/net/wireless/iwlwifi/pcie/rx.c
@@ -867,24 +867,23 @@ void iwl_disable_ict(struct iwl_trans *trans)
        spin_unlock_irqrestore(&trans_pcie->irq_lock, flags);
 }
 
+/* legacy (non-ICT) ISR. Assumes that trans_pcie->irq_lock is held */
 static irqreturn_t iwl_isr(int irq, void *data)
 {
        struct iwl_trans *trans = data;
-       struct iwl_trans_pcie *trans_pcie;
+       struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
        u32 inta, inta_mask;
-       unsigned long flags;
 #ifdef CONFIG_IWLWIFI_DEBUG
        u32 inta_fh;
 #endif
+
+       lockdep_assert_held(&trans_pcie->irq_lock);
+
        if (!trans)
                return IRQ_NONE;
 
        trace_iwlwifi_dev_irq(trans->dev);
 
-       trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
-
-       spin_lock_irqsave(&trans_pcie->irq_lock, flags);
-
        /* Disable (but don't clear!) interrupts here to avoid
         *    back-to-back ISRs and sporadic interrupts from our NIC.
         * If we have something to service, the tasklet will re-enable ints.
@@ -907,7 +906,7 @@ static irqreturn_t iwl_isr(int irq, void *data)
                /* Hardware disappeared. It might have already raised
                 * an interrupt */
                IWL_WARN(trans, "HARDWARE GONE?? INTA == 0x%08x\n", inta);
-               goto unplugged;
+               return IRQ_HANDLED;
        }
 
 #ifdef CONFIG_IWLWIFI_DEBUG
@@ -926,18 +925,13 @@ static irqreturn_t iwl_isr(int irq, void *data)
                 !trans_pcie->inta)
                iwl_enable_interrupts(trans);
 
- unplugged:
-       spin_unlock_irqrestore(&trans_pcie->irq_lock, flags);
-       return IRQ_HANDLED;
-
- none:
+none:
        /* re-enable interrupts here since we don't have anything to service. */
        /* only Re-enable if disabled by irq  and no schedules tasklet. */
        if (test_bit(STATUS_INT_ENABLED, &trans_pcie->status) &&
            !trans_pcie->inta)
                iwl_enable_interrupts(trans);
 
-       spin_unlock_irqrestore(&trans_pcie->irq_lock, flags);
        return IRQ_NONE;
 }
 
@@ -963,15 +957,19 @@ irqreturn_t iwl_isr_ict(int irq, void *data)
 
        trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
 
+       spin_lock_irqsave(&trans_pcie->irq_lock, flags);
+
        /* dram interrupt table not set yet,
         * use legacy interrupt.
         */
-       if (!trans_pcie->use_ict)
-               return iwl_isr(irq, data);
+       if (unlikely(!trans_pcie->use_ict)) {
+               irqreturn_t ret = iwl_isr(irq, data);
+               spin_unlock_irqrestore(&trans_pcie->irq_lock, flags);
+               return ret;
+       }
 
        trace_iwlwifi_dev_irq(trans->dev);
 
-       spin_lock_irqsave(&trans_pcie->irq_lock, flags);
 
        /* Disable (but don't clear!) interrupts here to avoid
         * back-to-back ISRs and sporadic interrupts from our NIC.